Buzzing Sound From Rear When Truck is Off?

Hey fellow Gen 3 owners,

As the title says, I periodically hear a buzzing sound coming from the rear of my 2023 1794 when the truck is parked and everything is off. Starting the engine, then shutting it off again, causes the noise to stop.

Do any of you have any idea what could be causing this? Failing wheel sensor? Or.....???

Thanks in advance,

Matt

 

is it 5 or so hours after key off? Might be the EVAP pump and/or purge valve cycling. Does this on gen 2.5 and my wifes 2017 Rav4 after 5 hours of key off. Might be different for the gen 3 tundra.

 

my 2023 hybrid 1794 makes all kinds of "robot" noises when i turn it off and for a few minutes after its been off. I think it's normal. Also, when I first open the drivers door, it makes a funny noise. As someone mentioned earlier, I think it's fuel pump priming up or something like that.

 

I haven’t heard mine do it, but my wife’s Subaru Crosstrek Evap test is very distinct. I bet it’s this, I have been always trying to hear if my truck does it. There are a few little parts between the Sub and the Toy that are the same, so I have been wondering if they shared Evap test.

 

My 2022 does it, my wifes Lexus makes all sorts of noises days after its been driven. Until I hear it start and back out of the garage i plan to ignore it

 

YESSS! Mine Does!! I took a picture of the module it was coming from...Sounds like a very tiny and small air compressor. Truck had been off and unused for hours. Meant to start a post here but forgot

 

Evap for the fuel tank.

 

I have had a few newer Toyotas recently and they also have made similar noises. Quite a while after shut off (hours) the EVAP system buzzes for what seems like a few min at a time. Also more quickly after shut down I hear a much louder and shorter duration noise that sounds like the electronic rear parking brake tightening up. It is a loud creaky sound from the back. Not sure what it is but our RAV4 Prime also did it so assume it is completely normal.

The louder creaky sound scares my outside cat who gets under the car for some warmth but bothers me quite a bit less.

 

I was under the impression that it was the E break locking down/re adjusting after being parked for several minutes,I dunno.

 

Thanks for the responses, folks.

Yes, the noise happens after the truck has been sitting for several hours. As a matter of fact, I just heard the same noise coming from my wife's 2022 4Runner this morning. So, apparently it is an EVAP function, and is perfectly normal. That's good to know.

This forum is one of the best on the inter-webs.

Matt

 

I took a video of this but cannot upload the file type. I came across this for the 2nd time since purchasing the truck. Small air compressor noise is the best I would compare it to as well.

 

I continue to make noises long after I've shut down and parked my ass for the evening as well.
All normal.

 

Just another stupid EPA required worthless pos that will eventually fail or get stuck on running down the battery and costing the consumer $. My 2003 Tacoma always starts because when you turn it off it's off lol.

 

I heard the air compressor like sound in my garage one night and was like wtf. So I restarted the truck and then shutdown after the idle stabilized. Didn't hear the noise after that. I didn't think to check the fuel gauge when this happened, but wondering if this is more prevalent with certain fuel levels.

 

Glad I checked this forum before tearing apart my garage. I was convinced I left my roadside compressor on. Problem is it sits in a bin in the garage attic!! Would never have guessed an evap function 6 hours after I last used the truck.

 

Just noticed mine doing same thing tonight. I pressed brake to start and it stopped when I Pressed on brake. Assume from this thread everything is normal And it’s a designed function.

 

As mentioned, the buzzing sound heard several hours after driving is a normal EVAP purge test. A small pump creates pressure changes in the fuel system to detect leaks.

My question is, how much draw does this system put on the battery? And is it possible to disable the EVAP test without throwing codes?